蜡梅花香及花色色素成分的初步研究

采用顶空固相微萃取吸附6个蜡梅基因型鲜花的香气成分,用色谱/质谱联用仪分析鉴定。结果共检出45个成分,其中鉴定了37个,只有18个共同出现在6个样品中。帖烯在花香中起主导作用,其中反式β-罗勒烯和芳樟醇的含量丰富,另外苯环型化合物乙酸苄酯也在花香成分中占有大的比重。但是各个主要组分在不同的基因型中相对含量差异很大,结果表明不同蜡梅基因型的花香成分存在质和量的变化。此外,选取在颜色表现性状上具有代表性的蜡梅中、内被片,通过一系列的颜色反应和紫外-可见光光度计在200~600nm范围内的扫描光谱分析。结果表明:蜡梅花色色素主要是黄酮类化合物,含有橙酮或/和查耳酮、二氢黄酮或/和二氢黄酮醇及具有邻二酚羟基的黄酮类物质,可能含有黄酮、黄酮醇、异黄酮;杏黄色和黄绿色的花被片(包括中被片和内被片)中还含有微量的叶绿素a,而其他色泽的花被片中不含有叶绿素a;乔种和红心类蜡梅的内被片中还含有花色素及其苷类,且颜色的深浅与其花色素及苷类的含量呈正相关。     

多花蔷薇花挥发油化学成分的GC／MS分析

本文采用ＧＣ／ＭＳ技术，分析了经并时蒸馏萃取装置获得的多花蔷薇挥发油化学成分。共鉴定出２８种化合物，为开发、利用这一野生资源提供了科学依据。     

白玫瑰挥发油化学成分的研究

本研究采用GC/MS/DS联用技术,分析了白玫瑰花挥发油的化学成分。从分离的的44化合物中,鉴定了41个组分,占挥发油总含量的97.64%。白玫瑰挥发油的主要成分是β—笨乙醇,含量高达86.53%,其次是丁香酚(4.75%)和香叶醇(2.45%)。     

Comparisons of Three Recurrent Selection Methods in the Improvement of Maize Populations

The maize population Csyn 4 was improved for three cycles with three recurrent selection methods MS1, MS1-HS, and MHSRRS in northern China. A total of 40 NC Ⅱ testcrosses were made by four testers with Csyn 4 and 10 improved populations, which were evaluated in four environments in the cropping season of 2005. Analysis of variance indicated a significant progress （P〈 0.05） in yield and other chief agronomic traits in the improved populations and testcrosses, demonstrating that the three recurrent selection methods were effective for increasing grain yield of testcrosses and improvement of general combining ability in maize population. The average grain yield increase of population Csyn 4 in MS1, MS1-HS, and MHSRRS recurrent selections was 266.7 kg ha^-1 （5.3%）, 288.0 kg ha^-1 （5.7%）, and 231.3 kg ha^-1 （4.6%） per cycle, while the grain yield of S 1 progeny of population for Csyn 4 was increased by 420.0 kg ha^-1 （10.9%）, 376.0 kg ha^-1 （9.8%）, and 414.7 kg ha^-1 （10.8%） per cycle in MS1, MS1-HS, and MHSRRS recurrent selections, respectively. Linear responses （b） in the MS1, MS1-HS, and MHSRRS recurrent selections were the same as the realized responses of the selection （G） for grain yield increase of Csyn 4 and S1 progeny of the populations. The grain yield of testcrosses increased by 3.3-5.2% on average per cycle. The value of heterosis did not display any differences amongst the different cycles of selections. The GCA for yield component traits of population Csyn 4 was improved significantly by means of three selection methods, whereas the GCA for plant height, ear height, days to silking, and days to pollen did not show significant increase in the recurrent selections. GCA for the number of tassel branches were decreased in the selections, while GCA for the number of plant leaves were increased, but the difference was not significant.     

SPE-UPLC-MS法同时检测乳制品中11种三嗪类除草剂的残留

优化固相萃取(SPE)条件,采用SPE前处理,结合超高效液相色谱-质谱联用法(UPLC-MS)检测乳制品中11种常用三嗪类除草剂,即西码津、莠去津、西草净、阿特拉津、仲丁通、扑灭通、莠灭净、扑灭津、特丁津、扑草净、特丁净的残留量.分析方法为:经过Varian Plexa SPE柱处理的乳制品,用Waters BEH C...     

Factors affecting in vitro adventitious shoot formation on internode explants of Citrus aurantium L. cv. Brazilian

The in vitro formation of newly formed adventitious buds and shoots from internodal branch segments was studied on 12-month-old plants of Citrus aurantium L. cv. Brazilian. The effects of 6-Benzyladenine (BA) and α-Naphthalene acetic acid (NAA) treatments were evaluated on adventitious bud and shoot regeneration. High rates of bud initiation and shoot development were obtained both with BA supplemented medium, in the range from 1 mg L⁻¹ to 3 mg L⁻¹, and with 0.1 mg L⁻¹ NAA supplemented medium. NAA concentrations above 1 mg L⁻¹ significantly reduced bud initiation and shoot elongation. The results obtained using different in vitro culture vessels such as Petri dishes, tubes and glass culture jars were compared. The highest adventitious bud induction was observed in Petri dishes for internodes cultured in 2 mg L⁻¹ BA supplemented medium, with 95% responsive explants forming 9.0 ± 2.4 adventitious buds. The adventitious buds observed in Petri dishes reached a maximum height of 1 mm, with no further development, while some of the adventitious shoots cultured in tubes and glass culture jars grew over 1 cm in height. A shoot regeneration gradient of the internodes collected along the branch axis was noticed, with basal ones exhibiting higher regeneration frequency.     

How do earthworms influence organic matter quantity and quality in tropical soils?

Earthworms are important regulators of soil structure and soil organic matter (SOM) dynamics; however, quantifying their influence on SOM cycling in tropical ecosystems remains little studied. Simulated rainfall was used to disrupt casts produced by Amynthas khami and their surrounding soil (control) into a range of small sized aggregates (50-250, 250-500, 500-2000 and 2000-5000 μm). To gain insight into how earthworms influence SOM biogeochemical composition in the aggregates, we carried out elemental and stable isotope analysis, and analytical pyrolysis (Py GC/MS). We also characterized their lignin component after oxidation with cupric oxide (CuO).The C content of smaller size fractions (<500 μm) in the control soil was higher than in the larger fractions. Our study therefore suggests that the aggregate hierarchy concept, which is used to understand soil aggregates and SOM dynamics in temperate soils, may not be applicable to the tropical Acrisol studied here. Earthworms modified SOM organization in soil aggregates. Although the isotope analyses were useful for highlighting SOM enrichment in the earthworm casts, aggregate fractions could not be classified according to particle size. Molecular analyses were necessary to indicate that SOM in all size fractions of casts consisted of relatively undecomposed material. Protection of the most labile SOM structures occurred in the smallest aggregate size fraction (50-250 μm). Py GC/MS showed that earthworm casts and control aggregates <2000 μm could be clearly distinguished according to the molecular properties of their SOM. Aggregates larger than 2000 μm, however, were most probably composed of all fractions and were not different. As a consequence, our results indicate that studies to determine the impact of earthworms on SOM turnover in soil are spatially dependant on the scale of observation.     

樟树根材苯/醇提取物的Py-GC/MS分析

对樟树根材的化学成分研究较少,制约了樟树根材高附加值产品的开发利用。采用Py—GC/MS三体联用技术研究了樟树根材的化学成分。樟树根经冷冻干燥除水,粉碎后于苯/醇溶液中进行提取处理,提取物滤液经浓缩、冷冻除水后,于热裂解器在550℃的He气流中进行热解,然后对热解产物进行GC/MS联机分析,采用色谱峰面积归一化法计算各组分的相对含量。分析结果表明,樟树根热解产物富含名贵生物医药、名贵香料成分,副产物不仅可用于高档化妆品和护肤品,还可用于生物医药以及食品、染料、工业溶剂等的原料。     

胶体金试纸条法和液相色谱-串联质谱法检测牛奶中四环素类药物残留比较

采用胶体金试纸条与液相色谱-串联质谱（LC-MS/MS）两种方法检测牛奶中残留的四环素类药物。结果表明：胶体金试纸条的检测限为四环素40μg/L、强力霉素40μg/L、金霉素40μg/L、土霉素80μg/L;LC-MS/MS法在牛奶中四环素、强力霉素、金霉素、土霉素的检测限为50μg/L。采用两种方法对实际样品检测,检测结果一致。与液相色谱-串联质谱法相比,胶体金试纸条具有操作简便、快速、直观的特点,可作为筛选法对样品进行定性筛查,LC-MS/MS法进行阳性样品的确证和精确定量。     

超高效液相色谱-串联质谱法测定香蕉中壬基酚聚氧乙烯醚及其降解产物

为了研究壬基酚聚氧乙烯醚在食品中的残留量及安全性,通过乙腈提取、固相萃取法净化,建立了香蕉中壬基酚聚氧乙烯醚(NPnEO)及其降解产物壬基酚(NP)的超高效液相色谱-串联质谱(UPLC-MS/MS)测定方法,并对流动相、监测离子和校正曲线等进行了优化和探讨。结果表明:在5~40 μ g/kg添加水平范围内,NPnEO及NP的添加回收率在75%~117%之间,相对标准偏差(RSD)在3.2%~9.6%之间;NPnEO的检出限在0.005~0.04 μ g/kg之间,NP的检出限(LOD)为0.5 μ g/kg;该方法快速、灵敏,准确度高,符合残留检测的要求。